A versatile classification tool for galactic activity using optical and infrared colors

0582463 - ASÚ 2024 RIV FR eng J - Journal Article
Daoutis, C. - Kyritsis, E. - Kouroumpatzakis, Konstantinos - Zezas, A.
A versatile classification tool for galactic activity using optical and infrared colors.
Astronomy & Astrophysics. Roč. 679, November (2023), č. článku A76. ISSN 0004-6361. E-ISSN 1432-0746
Institutional support: RVO:67985815
Keywords : active galaxies * star formation * starburst
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 6.5, year: 2022
Method of publishing: Open access

In this work we used infrared and optical colors to build an all-inclusive galactic activity diagnostic tool that can discriminate between star-forming, AGN, low-ionization nuclear emission-line region, composite, and passive galaxies, and which can be used in local and low-redshift galaxies. We used the random forest algorithm to define a new activity diagnostic tool. As the ground truth for the training of the algorithm, we considered galaxies that have been classified based on their optical spectral lines. We explored classification criteria based on infrared colors from the first three WISE bands (bands 1, 2, and 3) supplemented with optical colors from the u, g, and r SDSS bands. From them, we sought the combination with the minimum number of colors that provides optimal results. Furthermore, to mitigate biases related to aperture effects, we introduced a new WISE photometric scheme that combines apertures of different sizes.Using machine learning methods, we developed a diagnostic tool that accommodates both active and passive galaxies under one unified classification scheme using just three colors. We find that the combination of W1-W2, W2-W3, and g-r colors offers a good performance, while the broad availability of these colors for a large number of galaxies ensures it can be applied to large galaxy samples. The overall accuracy is ~81%, and the achieved completeness for each class is ~81% for star-forming, ~56% for AGN, ~68% for LINER, ~65% for composite, and ~85% for passive galaxies.
Permanent Link: https://hdl.handle.net/11104/0350530